Multiple apoptotic pathways induced by p53-dependent acidification in benzo[a]pyrene-exposed hepatic F258 cells

J Cell Physiol. 2006 Sep;208(3):527-37. doi: 10.1002/jcp.20686.

Abstract

Polycyclic aromatic hydrocarbons (PAH), such as benzo[a]pyrene (B[a]P), are ubiquitous genotoxic environmental pollutants. Their DNA-damaging effects lead to apoptosis induction, through similar pathways to those identified after exposure to other DNA-damaging stimuli with activation of p53-related genes and the involvement of the intrinsic apoptotic pathway. However, at a low concentration of B[a]P (50 nM), our previous results pointed to the involvement of intracellular pH (pHi) variations during B[a]P-induced apoptosis in a rat liver epithelial cell line (F258). In the present work, we identified the mitochondrial F0F1-ATPase activity reversal as possibly responsible for pHi decrease. This acidification not only promoted executive caspase activation, but also activated leucocyte elastase inhibitor/leucocyte-derived DNase II (LEI/L-DNase II) pathway. p53 appeared to regulate mitochondria homeostasis, by initiating F0F1-ATPase reversal and endonuclease G (Endo G) release. In conclusion, a low dose of B[a]P induced apoptosis by recruiting a large panel of executioners apparently depending on p53 phosphorylation and, for some of them, on acidification.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / drug effects*
  • Benzo(a)pyrene / toxicity*
  • Caspases / metabolism
  • Cell Line
  • Epithelial Cells / cytology
  • Epithelial Cells / drug effects
  • Epithelial Cells / physiology
  • Hydrogen-Ion Concentration
  • Liver / cytology
  • Liver / drug effects
  • Liver / physiology*
  • Mitochondria, Liver / drug effects
  • Mitochondria, Liver / enzymology
  • Phosphorylation
  • Proton-Translocating ATPases / metabolism
  • RNA Interference
  • Rats
  • Transfection
  • Tumor Suppressor Protein p53 / metabolism*

Substances

  • Tumor Suppressor Protein p53
  • Benzo(a)pyrene
  • Caspases
  • Proton-Translocating ATPases